[U-Boot] [PATCH 1/9] arm926ej-s: Invalidate instruction cache in flush_cache

Michael Spang
2013-07-29T14:22:46Z

On Mon, Jul 29, 2013 at 10:09 AM, Albert ARIBAUD
<albert.u.boot@aribaud.net> wrote:
> Hi Michael,
>
> On Mon, 29 Jul 2013 08:57:53 -0400, Michael Spang
> <mspang@csclub.uwaterloo.ca> wrote:
>
>> Albert,
>>
>> That's not a correct characterization of the bug.
>>
>> The incoherent cache lines are from before the relocation stage. If
>> U-Boot is relocating from RAM, and later copies the OS there without
>> invalidating those lines, then that's a bug in U-Boot.
>
> Thanks for this pointing out this scenario, which is correct, although
> it was not raised in the original bug description.
>
> I begs however the question whether anything from re-relocation can
> survive in the icache from between the moment the relocation starts and
> the moment the OS is given transfer to. IOW, was this issue actually
> met?

Yes, I had boot failures without this patch on the device I was
porting to (TS-7800). It happened consistently.

>
> Anyway I stand by my statement that even if there is an issue to fix,
> this patch fixes it in the wrong place.

Ok, that's fair. I was hoping to repost this series someday and will
take that into account.

Michael